Pakistan says it has killed a rebel tribal leader during a combat operation in the southwestern province of Baluchistan.The tribal leader's death has sparked has widespread riots in the provincial capital, Quetta

The government has imposed a 24-hour curfew in the city of Quetta, to put down violence that erupted Saturday almost immediately after news of Nawab Akbar Bugti's death became public.

Hundreds of Bugti's supporters rioted throughout the night. At least a dozen buses and other vehicles were torched near the local university, and piles of burning tires blocked a number of key city roads.

Bugti, once governor of Baluchistan province, was a central figure in a violent campaign to secure greater control over the province's resources, including valuable natural gas deposits.

The central government calls him a terrorist, and accuses his supporters of targeting government outposts and destroying local infrastructure, including natural gas pipelines.